Heat oil in a Dutch oven over medium. Add onion, celery, carrots, and wild rice; cook, stirring occasionally, until vegetables are tender, about 10 minutes. Add butter, garlic, sage, and rosemary; cook, stirring constantly, 1 minute. Sprinkle with 1/2 teaspoon salt and 1/2 teaspoon pepper, and pour in stock. Increase heat to high, and bring to a boil. Cover and reduce heat to low; simmer 10 minutes.
Add brown rice; cover and simmer until rice is tender and most of the liquid has been absorbed, about 1 hour. Remove from heat; let stand, covered, 10 minutes. Stir in remaining 1/2 teaspoon salt and 1/4 teaspoon pepper; spoon onto a serving platter. Top with cherries, pecans, and celery leaves.